Spark plug



FIG. 1 is a side elevational view of the spark plug showing my newdesign;

FIG. 2 is a side elevational view thereof shown rotated 90 degreescounterclockwise from FIG. 1;

FIG. 3 is a top plan view thereof; and

FIG. 4 is a bottom plan view thereof.

Theornamental design for a spark plug, as shown and described.